diff --git a/include/znc/ZNCString.h b/include/znc/ZNCString.h
index 3eda9e51..e43d42f7 100644
--- a/include/znc/ZNCString.h
+++ b/include/znc/ZNCString.h
@@ -38,24 +38,6 @@ typedef std::set<CString> SCString;
 typedef std::vector<CString> VCString;
 typedef std::vector<std::pair<CString, CString>> VPair;
 
-static const unsigned char XX = 0xff;
-static const unsigned char base64_table[256] = {
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, 62, XX, XX, XX, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60,
-    61, XX, XX, XX, XX, XX, XX, XX, 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10,
-    11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, XX, XX, XX, XX,
-    XX, XX, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,
-    43, 44, 45, 46, 47, 48, 49, 50, 51, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
-    XX, XX, XX, XX, XX, XX, XX, XX, XX,
-};
-
 enum class CaseSensitivity { CaseInsensitive, CaseSensitive };
 
 /**
diff --git a/src/ZNCString.cpp b/src/ZNCString.cpp
index d71adf60..ef093f69 100644
--- a/src/ZNCString.cpp
+++ b/src/ZNCString.cpp
@@ -23,6 +23,24 @@
 
 using std::stringstream;
 
+static constexpr unsigned char XX = 0xff;
+static constexpr unsigned char base64_table[256] = {
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, 62, XX, XX, XX, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60,
+    61, XX, XX, XX, XX, XX, XX, XX, 0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10,
+    11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, XX, XX, XX, XX,
+    XX, XX, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,
+    43, 44, 45, 46, 47, 48, 49, 50, 51, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX,
+};
+
 CString::CString(char c) : string() {
     stringstream s;
     s << c;